On May 12, 2014, Dr. Thomas Caulfield notified PDF Solutions, Inc. (the
"Company") that he was resigning from the Company's Board of Directors effective
as of May 14, 2014. Dr. Caulfield is resigning because he is joining the
executive team at GLOBALFOUNDRIES, Inc., one of the Company's key customers, and
not as a result of any dispute regarding the Company's operation, policies or
practices.

At this time, the Board is not nominating a replacement Class I director for
election at the 2014 Annual Meeting. Other than Dr. Caulfield, the Class I
nominees named in the 2014 Proxy Statement will stand for election at the
meeting. Notwithstanding Dr. Caulfield's resignation and withdrawal, the form of
proxy card included in the Company's definitive proxy materials remains valid.

However, any votes that are or have been submitted with instruction to vote for
all of the Board's nominees will be voted only for the remaining two Class I
nominees, as named in the 2014 Proxy Statement, and any votes that are or have
been submitted with instruction to vote for Dr. Caulfield will be disregarded.

If you have already submitted your proxy, you do not need to take any action
unless you wish to change your vote.